Mobile communication technologies have been changing with the development and progress of science and technology and mobile phone is becoming a necessity in people's daily life. Low cost mobile phone is a major trend in the development of the mobile phone manufacturing industry. With the decrease in the mobile phone cost, mobile phones are becoming cheaper and cheaper to become easily affordable for users in more undeveloped areas, thus the popularization rate of mobile phones is largely increased. Most low cost mobile phones are bar phones, and it is possible to apply a broken-board structure in a main board of a bar phone with the increase of the integration degree of the related mobile phone chip. In other words, with the increase of the integration degree of the related mobile phone chip, different from the previous mobile phone main board which occupies the whole mobile phone area, the current mobile phone main board which applies a broken-board structure only occupies about a half of the whole mobile phone area. A main board having a broken-board structure is applied in a mobile phone to greatly reduce the manufacturing cost of the mobile phone. Generally, a support board for supporting the main board and components such as a display screen at the other end are required for a mobile phone which applies a main board having a broken-board structure. Since the support board used by the bar phone in the existing technology is only applicable to a main board with a relatively low chip integration degree, i.e., a main board of a mobile phone needs to occupy the total area of the mobile phone, the support board is not applicable to the mobile phone which applies the main board having the broken-board structure. In addition, the support board is high in cost and fails to completely satisfy the requirements of the low cost mobile phone. Therefore, a support board applied to a main board having a broken-board structure is needed urgently at present.